The two-dimensional electron gas (2DEG) formed at the interface between SrTiO3 (STO) and LaAlO3 (LAO) insulating layer is supposed to possess strong Rashba spin–orbit coupling. To date, the inverse ...Edelstein effect (i.e., spin-to-charge conversion) in the 2DEG layer is reported. However, the direct effect of charge-to-spin conversion, an essential ingredient for spintronic devices in a current-induced spin–orbit torque scheme, has not been demonstrated yet. Here we show, for the first time, a highly efficient spin generation with the efficiency of ∼6.3 in the STO/LAO/CoFeB structure at room temperature by using spin torque ferromagnetic resonance. In addition, we suggest that the spin transmission through the LAO layer at a high temperature range is attributed to the inelastic tunneling via localized states in the LAO band gap. Our findings may lead to potential applications in the oxide insulator based spintronic devices.
Ferromagnetic resonance driven spin pumping, a topic of steadily increasing interest since its emergence over two decades ago, remains one of the most exciting research fields in condensed matter ...physics. Among the many materials that have been explored for spin pumping, yttrium iron garnet (YIG) is one of the most extensively studied because of its exceptionally low magnetic damping and insulating nature. There is a great amount of literature in the spin pumping and related research fields, too broad for this review to cover. In this Topical Review, we focus on the YIG-based spin pumping results carried out by our groups, including: the mechanism and technical details of our off-axis sputtering technique for the growth of single-crystalline YIG epitaxial films with a high degree ordering, experimental evidence for the high quality of the YIG films, spin pumping results from YIG into various transition metals and their heterostructures, dynamic spin transport in YIG/antiferromagnet hybrid structures, intralayer spin pumping by localized spin wave modes confined by a micromagnetic probe, dynamic spin coupling between YIG and nitrogen-vacancy centers in diamond, parametric spin pumping from high-wavevector spin waves in YIG, and localized spin wave mode behavior in broadly tunable spatially complex magnetic configurations. These results build on the power and versatility of YIG spin pumping to improve our understanding of spin dynamics, spin currents, spin Hall physics, spin-orbit coupling, dynamic magnetic coupling, and the relationship between these phenomena in a broad range of materials, geometries, and settings.
Monoazo colorants with separate inbuilt ESIPT core were selected to examine the influence of azo group para to the hydroxyl group of ESIPT core and their effect on their spectral properties. They ...displayed absorption maxima in the visible region around 480–493 nm. 6a exhibited a broad peak along with a bathochromic shift of 40/90 nm in the solvents DMF and DMSO due to the existence of tautomeric equilibrium. They are sensitive to basic pH with a bathochromic shift of 30 nm. They are emissive in the deep red region (565–640 nm) accompanied by a Stokes shift of 62–121 nm in DMF and DMSO. More interestingly, they showed viscosity sensitive enhancement in emission in DMF: PEG 400 system in the deep red region. 6(a–c) exhibit higher quantum yield in viscous solvent i.e. 99% PEG 400 compared to that of DMF. 6a and 6c show viscosity sensitive (x) value of 0.522 and 0.513 respectively. The enhancement of emission intensity in the viscous solvent is due to charge transfer which was elucidated by polarity plots i.e. “Lippert-Mataga”, “Mac-Rae”, “Weller's” and “Rettig's” plots. DFT and TD- DFT methods were used to correlate the experimental findings.
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•ESIPT clubbed azo dyes with emission in deep red region.•Sensitive to basic pH with a bathochromic shift.•Viscosity sensitive enhanced emission in DMF: PEG 400 system in the deep red region.•Polarity plots were used to elucidate the enhancement of emission intensity in the viscous solvent.
Stochastically fluctuating wind power has a negative impact on power grid operations. This paper presents a wind power filtering approach to mitigate short- and long-term fluctuations using a hybrid ...energy storage system (HESS), and a novel wavelet-based capacity configuration algorithm to properly size the HESS. A frequency distribution allocates wind power fluctuations to the different HESS components to more easily satisfy 1-min and 30-min fluctuation mitigation requirements (FMR). An ultra-capacitor bank (UC) mitigates short-term fluctuations. In the HESS, and a lithium-ion battery bank (LB) minimizes long-term fluctuations. This paper also proposes a novel online-wavelet based coordination control scheme for the HESS, consisting of primary filtering (PF) and secondary filtering (SF) stages. The PF stage obtains a combined power output that fully satisfies the FMRs, while the SF stage provides additional smoothing of the wind power output fluctuations after the PF stage. A remaining energy level (REL) feedback control maintains the REL of the battery bank within its proper range. Case studies demonstrate that the proposed wavelet-based algorithm is more efficient than other published algorithms, and needs a lower energy storage capacity to satisfy 1-min and 30-min FMRs.
The determination of intrinsic Gilbert damping is one of the central interests in the field of spintronics. However, some external factors in magnetic films tend to play a remarkable role in the ...magnetization dynamics. Here, we present a comprehensive study of the magnetic relaxation in ferromagnetic films with various in-plane magnetic anisotropy via ferromagnetic resonance technique. We find that the magnetic drag effect can result in the resonant linewidth broadening and the nonlinear dependence of linewidth on frequency stemming from field-magnetization misalignment. As a result, this could lead to the imprecise extraction of the key dynamic parameter-Gilbert damping and cause the confusing behaviors of ultra-low and anisotropic damping in thin films and multi-layers with high magnetic anisotropy. Our results provide a crucial way for the accurately quantitative estimation of the Gilbert damping in spintronics measurements.
Yttrium Iron Garnet (YIG) ferrites, characterized by their superior magnetic and dielectric attributes, are instrumental in advancing the development of microwave devices, particularly in enhancing ...high-frequency performance, integration, and miniaturization. This paper synthesizes YIG ferrite materials with the composition Bi0.6Y1.4-xCa1+xFe4.5-xV0.5GexO12 (x = 0.10 to 0.50, incrementing by 0.10) through the solid-state sintering method. It delves deeply into the mechanism by which Ca2+-Ge4+ ions substitution regulates the magnetic properties of BiV-YIG. The microstructural and magnetic properties of the samples were systematically tested and analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), vibrating sample magnetometry (VSM), and TE106 perturbation method. At a substitution content of x = 0.50, the substitution of Ge4+ ions for the Fe3+ ions at the d-site transforms the material from ferrimagnetic to paramagnetic, and the saturation magnetization of the sample drops to 132.74 G. By calculating the ferromagnetic resonance (FMR) linewidth using the law of approach to saturation, the study elucidates the negative impact of low saturation magnetization on FMR linewidth. The mechanisms proposed in this paper provide theoretical and experimental bases for reducing the FMR linewidth of high dielectric constant Bi-substituted YIG, paving the way for developing high-dielectric, low-loss YIG ferrite materials for microwave devices.
When planning for brain tumor resection, a balance between maximizing resection and minimizing injury to eloquent brain parenchyma is paramount. The advent of blood oxygenation level-dependent ...functional magnetic resonance (fMR) imaging has allowed researchers and clinicians to reliably measure physiologic fluctuations in brain oxygenation related to neuronal activity with good spatial resolution. fMR imaging can offer a unique insight into preoperative planning for brain tumors by identifying eloquent areas of the brain affected or spared by the neoplasm. This article discusses the fMR imaging techniques and their applications in neurosurgical planning.
We report the magnetization dynamics study in Y3Fe5O12 (YIG) film grown by rf magnetron sputtering techniques. The growth-induced interfacial layer is believed to affect the top YIG layer, ...interrupting the magnetic properties associated with it drastically. The structural data confirmed the epitaxial and strained growth of YIG on a highly matched GGG (100) substrate. The frequency variation of the FMR signal yields various important parameters, such as the line width (ΔH), effective magnetization (4πMeff), and damping constant (α) at 300 K. The significant increase in 4πMeff to 2187.848 Oe reflects the presence of non-collinear or antiparallel arrangement of magnetic moment in YIG thin-film. Apart from this value of α was reported to be 1.5 × 10−3 which is substantially higher than the values reported in the literature for such higher-quality epitaxial thin films. We anticipate that a detailed analysis of these findings will provide excellent speculation in the field of magnonics, advanced spintronics and terahertz frequency-related applications.
In this study, a series of Li0.43Zn0.27Ti0.13Fe2.17O4 ferrites were successfully synthesized by solid-state reaction method at 920 ℃ employing low melting point V2O5 as sintering aid. The X-ray ...diffraction (XRD) studies demonstrated that all samples exhibited spinel phase. Microscopic image analysis revealed that both the grain growth and uniformity were significantly promoted. The average grain size was increased from 0.65 µm to 4.53 µm when V2O5 was increased from 0.0 wt% to 2.4 wt%. In terms of the magnetic properties, the saturation magnetization (4πMs) of the samples increased from 2915 Gs to 3434 Gs, the coercivity (Hc) decreased from 848.3 A/m to 242.2 A/m, and the ferromagnetic resonance linewidth (ΔH) decreased from 963 Oe to 543 Oe. It could be noted that the proper addition of V2O5 is the key to optimizing the microstructure and magnetic properties of LiZnTi microwave ferrite. Therefore, as an effective additive, V2O5 can promote the development of low temperature co-fired ferrites.
•Microstructure of LiZnTi ferrite was improved by V2O5 doping. Grain growth and uniformity were obviously promoted.•Magnetic properties, including 4πMs and Hc, were optimized by V2O5 doping.•Ferromagnetic resonance linewidth (ΔH) was decreased significantly by V2O5 doping.
•The magneto-impedance of a CoP@Cu core–shell microwire was investigated.•The long term stability of the CoP metallic amorphous alloy was tested.•A microstrip waveguide was used for measuring the ...magneto-impedance.•Giant magneto-impedance effect yielded values as high as 98 % for f = 30 MHz.•The Kittel formula for a plate geometry accounted for FMR in the microwave regime.
The giant magneto-impedance effect (GMI) consists in a large variation in the electrical impedance that occurs in some magnetic materials when subjected to a variable external magnetic field. Here we present an experimental study of the GMI in a wide frequency range observed in a structure of the metallic amorphous magnetic alloy CoP electrodeposited on copper microwires by using a microstrip configuration. In the low frequency range, the magnetic field dependence of the impedance is due to the behavior of the circumferential ac susceptibility in the magnetic coating. In the microwave range the behavior of the GMI is dominated by the main dynamical magnetic phenomenon at high frequencies, namely ferromagnetic resonance (FMR). The experimental data are well fit by Kittel equation for the FMR frequency for a ferromagnetic layer with a saturation magnetization similar to the ones reported in previous works. The structural stability of the CoP alloy against aging effects was also investigated. The overall results indicate that the CoP alloy is a good candidate for applications in sensors and in microwave devices.
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